The election judge supervisor has not been identified, though St Charles County has confirmed the worker tested positive for coronavirus on October 30.
The county also confirmed the death of the worker, but said the cause of death is yet to be confirmed.
The judge was advised to quarantine for 14 days after testing positive, however neglected to do so and worked on election day.
“The election judge nevertheless failed to follow the advice and worked at the County’s Precinct 41 at the Blanchette Park Memorial Hall polling site in St Charles on Election Day,” the county’s statement said.
Election workers at the polling site have been contacted by the Department of Health epidemiologists.
The judge’s family is working with health authorities to determine their whereabouts prior to the positive test results.
The county said contacts may include some or all of the nine other election workers at the polling site, who are all advised to get tested.
However, it is unlikely some 1800 people who cast their vote at Blanchette Park Memorial Hall on election day will be considered close contacts, though the county advises anyone who was at the precinct to watch for symptoms.
“It is not anticipated that close contacts will include any of the 1,858 voters who were at the polling place Tuesday, as the worker was a supervisor with job duties that do not typically include working closely with voters, handling iPads, distributing styluses, or taking voter identification,” St Charles County said.
Election workers were all required to wear face masks or shields at all times while working the polls and workers and voters were separated by Plexiglas barriers, St Charles County Director of Elections Kurt Bahr said.
St Charles County Director of Public Health Demetrius Cianci-Chapman said those who test positive for Covid-19 are required to be responsible for others in the community.
“As this virus continues to spread, all aspects of the healthcare system are working together to remind the community that a positive COVID-19 test result requires that person to be responsible to others in the community,” the director said.
“There is no more important duty than protecting the health of our families, friends and those who reside in the community with us.”
The US continues to lead the world in coronavirus infections with over nine million, according to John Hopkins data.
Missouri has recorded over 200,000 Covid cases since the start of the pandemic, while St Charles which has a population of more than 400,000 people has had over 12,000 cases.
On Wednesday, the day after the presidential election, the US set a new one-day record for new coronavirus cases with at least 102,591 infections.
In addition to rising cases, on Tuesday hospitalisations topped 50,000 for the first time in three months in the US.
North Dakota reported only six free intensive care unit beds in the entire state on Wednesday, when it was one of 14 states that reported record levels of hospitalised COVID-19 patients.
Hospitalisations are a key metric because they are not impacted by the amount of testing done.
The pandemic has affected nearly every aspect of American life, including a record number of voters mailing in their ballots in Tuesday's presidential election.
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